When the playbase stops working.

in meanwhile get a sub and rear SLs  

I've got gen2 sub & two sonos1s 

I've got gen2 sub + 2 sonos 1s

I replaced playbar with ARC and quite satisfied but without TV with eARC and only feeding with optical you can probably wait. 
 

maybe a pair of Moves or 5s?

I'd at least wait until a deal or voucher code comes your way. Or see if Sonos can provide a refurb.

Does your TV support eARC or HDMI-ARC? If not the there is no point at all as you’ll just be using optical.

Thank you for taking the time to reply. 

My samsung TV is only a few months old so I'm hoping it does support those things.

What input does the arc use??.

I'm sorry but I'm not to clued up on these things. 

My set up is playbase, sub & two sonos1s. 

Will I notice much difference with the arc????